Chinese Foreign Ministry spokesman Qin Gang said all parties involved in the dispute should step up negotiations and dialogue.

Iran announced plans on Sunday to build 10 new uranium enrichment plants in a big expansion of its atomic program, two days after the U.N. nuclear watchdog rebuked it for carrying out such work in secret.

China supported the resolution of the International Atomic Energy Agency's board in a rare public show of exasperation at Iran.

But Qin's comments suggest the world's number two oil consumer still has a limited appetite for confrontation with one of its biggest suppliers of crude. Iranian oil made up nearly 12 percent of China's crude imports last year.

"(China) advocates resolution of the Iran nuclear issue through dialogue and negotiations," Qin told a regular news conference in the Chinese capital.

"We believe that all sides must continue enhancing diplomatic efforts. Sanctions are not the goal."

Beijing faces a tricky balance over Iran with Western countries urging it to back stiffer pressure, and possibly fresh U.N. sanctions, aimed at curtailing Tehran's nuclear program, which critics say is aimed at amassing the technology to make nuclear weapons.